One type of processor-controlled system is the telecommunication switching system. Modern telecommunication switching systems generally comprise peripheral equipment, including a switching network, and a central processor. The central processor controls the peripheral equipment by transmitting peripheral unit control signals over a bus which interconnects the processor and the peripheral equipment. The switching network may include a plurality of interconnected switching circuits, each comprising several grids of switches and a peripheral unit controller, for establishing transmission paths through the network. Peripheral unit controllers are responsive to peripheral unit control signals from the central processor to provide the necessary pulses to operate switches in each of the grids, as defined by the control signals.
Typically, a telecommunication system switching network is capable of handling high-peak traffic loads occurring only at certain times and has excess capacity at other times. In order to save energy, it is desirable to apply power only to the active elements of the switching network. However, it is not feasible to remove power from any large portion of the network and to restrict network activity to the remainder portion. Furthermore, any portion of the network which is not in use must at all times be immediately available for use in the event of an increase in traffic load.